Is it possible that the weather forecast will snow today and be sunny tomorrow?

It's quite possible. Weather forecasts are often inaccurate.

Although the accuracy of our current weather forecast has been greatly improved compared with the past, the atmospheric system is a very complicated system after all, and it is inevitable that the weather forecast is inaccurate. At present, human understanding of the atmospheric system is still in the primary stage, and the history of making weather forecasts is only 160 years. Weather forecasting technology has a great development space in the future, and it is still in the process of continuous development.